How did monkey experiments distinguish learning from observation from simply copying another monkey?

In studies of animal learning, researchers distinguish between observational learning and simple imitation by analyzing whether an animal is merely copying an action or actively using information gained from observing an outcome.

A key experiment involved two monkeys taking turns as demonstrator and observer. The demonstrator had to choose between two objects to find hidden food; because the objects changed each trial, the demonstrator chose randomly. The observer watched the demonstrator’s trial to identify the correct object.

Researchers determined the observer was learning from the outcome rather than simply copying the demonstrator’s actions because the observer performed more accurately on trials where the demonstrator’s choice was wrong. If the monkeys were merely imitating, they would have copied the demonstrator’s choice regardless of whether it was correct or incorrect. This finding demonstrates that the observer was actively processing the results of the demonstrator's behavior to inform its own future choices, rather than blindly mimicking the physical movements observed.1